One problem encountered with ingredient cartridge systems is the handling of that cartridge in an extraction device and the closing of the latter around the cartridge to perform the extraction process and then the proper evacuation of the cartridge from the extraction device. The cartridge usually has to be positioned by the user on a cartridge support or in a housing, then the device is closed manually or automatically around the cartridge.
It is important to correctly position the cartridge so that the device closes properly around the latter and to form a good seal to ensure good conditions of extraction. Bad positioning may damage the cartridge, and thus affect the conditions of extraction.
For the sealing of the device around the cartridge to permit proper extraction by passing a pressurized liquid through the cartridge without undesired leakage, the closing of the device around the cartridge must be carried out with a high level of precision. The closing distance of the mechanical closing arrangements of such devices are usually manually adjusted during the manufacturing process of the device to achieve the required level of precision. The loading of the capsule must also be easy, without trial and error as to the correct position of the capsule in the device. The loading must also be as rapid as possible and not require excessive manipulations.
WO 2005/004683 relates to a capsule brewing device comprising: a first part; a second part that can be moved relative to the first part; a housing for the capsule and defining, in a closed position of the movable part against the fixed part, an extraction position of the capsule along an axis in said housing; an insertion and positioning part comprising means for guiding the capsule arranged so as to insert the capsule by gravity and position said capsule in an intermediate position; a drink pouring system; and the second movable part is so arranged and constructed to move the capsule from the intermediate position into the extraction position when the device is closed. EP 1 721 553 discloses a brewing unit for coffee machines using capsules. The unit has a front part with a beverage outlet and a rear part with a hot water inlet. The front part and the rear part are mounted in-between a pair of facing shoulder guide members. The front part is movable in-between these guide members to be urged against the rear part so as to form with the rear part a brewing chamber for accommodating a capsule to be extracted, whereby an unoccupied volume is left in front of the front member between the guide members within the machine.
EP 1 659 547 relates to a beverage machine for making infusions, in particular, espresso coffee. The machine includes an infusion chamber within a brewing unit that has a movable front part with a return spring and a beverage outlet duct that extends through the assembly's outer housing. The movable front part cooperates with a rear part that is movable within the housing and that can be pushed against the movable front part to compress the return spring whereby the outlet duct slides through the assembly's outer housing. The pod is passed through the external housing to the infusion chamber via a rigid pod feed channel and then the pod is transferred into the infusion chamber by an external bushing on the movable rear part of the brewing unit which is provided with a cam-like path for moving the rear part. This arrangement involves several problems. The pod must be moved during the closure of the brewing chamber and this can cause blocking and it also makes the retaining means of the pod more complex. Moreover, opening and closing the brewing chamber involves simultaneously a linear displacement of the movable rear part within the housing, of the movable front part within the housing and of the outlet duct through the housing which increases the risk of hyper-guiding and jamming or improper alignment of the various parts that linearly move one relative to another. The fluid system comprises a moving assembly which makes the fluid system more complex to assemble. When upon extraction brewing unit is re-opened for removing the pod, pressurized water contained within the infusion chamber may project outside the housing. Furthermore, an unoccupied volume is left within the machine between the front member and the casing when the outlet duct is in its retracted position.
U.S. Pat. No. 3,260,190 and WO 2005/072574 disclose a coffee machine having a removable drawer for positioning a coffee can therein. The drawer can be slid horizontally into the coffee machine and lifted towards a water injection arrangement.
WO 2006/023309 discloses a coffee machine with a slidable drawer for the introduction of a coffee cartridge into the machine. The drawer is movable between an open and a closed position and has two cartridge half-shells that are pivotable against each other to form a brewing chamber when the drawer is in the closed position and pivotable apart when the drawer is slid out from the machine.
U.S. Pat. No. 6,966,251 discloses a coffee machine having a horizontally slidable drawer for positioning a capsule therein. When slid into the machine, the drawer can be moved upwards towards a fixed capsule cage for form a brewing chamber for a capsule. EP 1 566 126 discloses a coffee machine with a vertical brewing unit for accommodating coffee pods. The brewing unit has a fixed upper part and a movable lower part for holding a pod and that can be pulled up for closing the brewing unit and let down for inserting or removing a pod.
Further brewing units are disclosed in EP 0 730 425, EP 0 862 882, EP 1 219 217, EP 1 480 540, EP 1 635 680, EP 1 669 011, EP 1 774 878, EP 1 776 026, EP 1 893 064, FR 2 424 010, U.S. Pat. No. 3,260,190, U.S. Pat. No. 4,760,774, U.S. Pat. No. 5,531,152, U.S. Pat. No. 6,904,840, U.S. Pat. No. 7,131,369, US 2005/0106288, US 2006/0102008, WO 2005/002405, WO 2005/016093, WO 2006/005756, WO 2006/066626 and WO 2007/135136.
To avoid the problem relating to precise mechanical closing of the extraction device around an ingredient cartridge, it is known to provide a hydraulic closure system in which the heated water used for extracting an ingredient in a cartridge is also used to actuate a hydraulic closure mechanism. In this case, the closing distance does not require special adjustment since the hydraulic closing force urges the cartridge supports of the extraction device together around the cartridge. An example of such a system is for instance disclosed in WO 2008/037642. Various systems have been developed along this idea, as for instance discussed in EP 1 219 217, EP 1 353 591, EP 1 480 540, EP 1 545 278, EP 1 776 026, EP 1 912 542, WO 2005/115206, WO 2006/005736 and WO 2011/042400.
Another problem is related to the optimal extraction of brewable ingredients supplied within a cartridge into the extraction device. On the one hand, there is a logistic and production need to maximize the filling of cartridges with ingredient so as to minimize the cartridge size/ingredient mass ratio, whereby packaging material and volume of the cartridge for storing and shipping can be minimized. A solution to this problem is compacting the brewable ingredient in the cartridge. On the other hand, to circulate an extraction fluid, e.g. heated water, through the cartridge, the brewable ingredient should not be compacted to such an extent as to form a more or less impervious mass. Of course, it is possible to increase the pressure of the circulating extraction fluid to an extent sufficient to overcome the barrier formed by the ingredient mass in the cartridge. However, this approach leads to a significant slow down of the extraction speed and beverage preparation due to the pressure drop through the ingredient mass. Moreover, significantly forcing the extraction fluid under high pressure through the brewable ingredient leads to extraction of undesirable solid compounds of the brewable ingredient which affect the taste of the beverage that becomes too strong and harsh. This latter phenomenon is known in the art as “over-extraction”.